How important is it to cover all the way up the firewall?

How important is it to cover all the way up the inside of the firewall with Dynamat? (firewall is behind the dash) Or whatever you may be using for your sound deadening. Here are some pics of a stripped cab that was redone on an old 73-87 chevy truck, much like the one that I am restoring now. The task of gutting the dash like this guy did seems very intimidating to me. Do most people just do the floor, and the trunk if they have a car? Maybe the roof and the doors? How many of you do all the way up the firewall? I know many of you here are very experienced with sound deadening, and I just wanted to get your opinion on how important it is. I will probly just have to do the floor/doors/back of the cab/roof and leave the firewall out. Thoughts? Opinions?

EDIT:

Don't consider the floor, I can do that myself. Just behind the dash. In the pics it shows the guy did the floor, that's no problem for me.

Re: How important is it to cover all the way up the firewall?

Really shouldn't be that big a deal if you can't get clear up there. I know I wouldn't take my whole dash out.

Originally Posted by danyopjr

Kickers are not meant to last that long so therefore seems like this sub is either abused with running too much watts to em or have been used for awhile. Kickers are ok for the price but wont last long when running them for awhile or running too much Watts to em